From Mechanical Database
|The EGR system lowers the NOx emissions from the tailpipe by injecting some inert gas into the combustion chamber, therefore cooling the burn temperature. If you live in an area that does emissions testing, chances are this modification won't pass.
Also, you might cause your catalytic converter to fail prematurely. There is an element called Rhodium in your three way cat. The excess NOx might cause it to fail. A new catalytic converter might cost $ 150, sale and installation of used catalytic converters is illegal in the U.S.
The EGR (Exhaust Gas Recirculation) emissions system puts soot back into the intake along with the exhaust gasses it recycles. As this soot is combined with oil vapors from the PCV system and the combustion process itself, a thick layer of sludge forms all over the walls of the intake manifold, ports, and valve stems. In high mileage engines that consume more oil than usual this can lead to enough buildup to cause performance issues.
- Remove the intake duct.
- Remove the exhaust manifold heat shield.
- It is secured by 10mm nuts with protruding studs, this will usually require a wrench or a deep socket.
- If the nuts will not move, they will usually just break the studs. This is ok as the heat shield is pretty useless and not worth reinstalling anyways. The temperatures beneath the hood may increase by a very slight amount but will not cause any long term effects.
- Remove the 2 bolts holding the EGR valve to the intake manifold and vacuum line from valve.
- Remove the 2 bolts holding the EGR tube to exhaust manifold.
- Remove the 2 rubber hoses from EGR tube near the valve. Mark upper and lower hoses to avoid mixing them up.
- Remove the EGR tube and valve from vehicle.
- Plug the hole in Exhaust manifold. This is best done by making a small flange block-off plate. Any small piece of metal with a decent thickness and two properly drilled holes will do. Or the EGR tube flange can be cut off and either tapped to facilitate a threaded plug or welded with an inserted bolt to create a seal.
- Cut the EGR tube about half-way down. Keep the end attached to the Valve. Do not cut off the nipples for the DPFEGR Sensor.
- Make a length of rubber tubing from the cut-off end of the EGR tube to the intake tube AFTER the MAF sensor.
- Reinstall the EGR valve and tube back into the vehicle.
- Re-attatch the vacuum hose to the EGR Valve.
- Replace the intake tube and attach the new hose from the EGR Tube to the intake.
With those modifications, he Engine Computer will still call for the EGR valve, but it will now be injecting metered clean air instead of exhaust gasses, keeping every part of your engine's air induction system from getting dirtier. This modification has been tested for over 9 months and 60,000 miles without a single instance of a CEL (check engine light).
Possible effects are more mid-throttle pickup and better off-idle throttle response.
For those reading with a ZX2 or a Zetec engine, wondering where their EGR system is, the EGR in Zetec engines is done by the VCT controller which retards the exhaust cam a bit to hold some of the exhaust gasses in the chamber. This is a good system as it eliminates the need for any soot creating components in the intake manifold.
With some emissions checks on OBD-II the exhaust gasses are not checked, but rather the car is scanned for any OBD-II trouble codes. This varies by area, but if this form of testing is used then the vehicle will pass an emissions test. However in some cases the system actually checks the upstream and downstream O2 sensor readings, which can result in an OBD-II equipped car to fail the test, despite not having a CEL.
As far as the catalytic converter goes, while damage is a possibility, the typical recommended lifespan of a catalytic converter is 60-100 K miles, and most owners are far past that already anyways so most likely no difference will be noticeable. the tailpipe using both the Upstream and downstream O2 sensors.
- Ford Escort & ZX2 section for the entire index of all Ford Escort and ZX2 related articles.